This invention relates to copper alloys and a process for the production thereof. The term "copper alloys" herein used includes in the strict sense both copper and copper alloys. However, either one of them will simply be referred to as this term hereunder. In particular, the invention relates to copper alloys that can provide surfaces having improved characteristics suitable for the production of various types of electrical parts, such as, a surface exhibiting decreased friction during insertion and drawing, for example, a surface of a multi-pin connector used for electric wiring in an automobile production; a surface of a charging-socket of an electric automobile which is used repeatedly a great number of times in insertion and drawing; a surface of a brush which is used in contact with a rotating body such as an electric motor and therefore is required to be highly resistant to abrasion; and a surface of a battery terminal which is also required to be highly resistant to abrasion and corrosion. The invention also relates to a process for the production of copper alloys referred to above.
With the recent development of the electronics industry, electric wiring in various machines is becoming more and more complicated and highly integrated, and this has caused use of connectors having an increased number of pins. Conventional connectors having Sn-plated surfaces have encountered a problem in that the practical use thereof is becoming more and more difficult because of the increased friction at the times of insertion and drawing.
Currently available electric automobiles require charging at least once a day. Thus, it is necessary that a charging-socket is highly resistant to abrasion. In addition, since a large amount of electric current such as 10 A or more flows in sockets and therefore a large amount of heat is generated, a new problem that Sn-plated surfaces of sockets obtained by a conventional method cannot withstand the delamination of the plated surface has occurred.
A deeper understanding has been acquired with respect to the fact that the above-stated problems cannot be solved by conventional surface treatment methods. A method of the kind of the present invention was also among the conventional methods, which comprises the steps of applying heat treatment to a copper alloy and subsequently causing heat diffusion in the alloy. However, the conventional method was no more than the method for only preventing the separation or peeling off, due to the influence of working or heat, of the surface treated layer from the alloy body by making use of the diffusion between the surface treated layer and the matrix. For this reason, the stated problems could not be solved by said prior art method.